The development of Voice over IP (VoIP) technologies, accompanied by the fusion of voice and data networks into the next generation converged networks, offers opportunities of developing new converged voice and application services. Exemplary concepts which are currently being developed are Rich Calls integrating different content types, Push-to-Video enabling one-to-one or one-to-many transmission of video data with the push of one key or Online Conferencing based on VoIP.
Concurrent access to several types of services in known value added services like those mentioned above typically is provided with one and the same terminal device. Accordingly the use of standard telephones typically is insufficient and instead terminal devices with special capabilities like computing power or sophisticated graphical user interfaces are needed.
Especially for the combination of application and telephony services today so called collaboration or conferencing applications are utilized. For instance WO 2004/051531 A2 describes a method for collaboration integration is known, wherein a session initiator selects the required services prior to session establishment and sends a collaboration request. In response to receiving the collaboration request a corresponding collaboration service is selected from multiple available collaboration services offered by multiple service providers. In EP 1 377 005 A1 a telecommunication system for collaboration using Instant Messaging (IM) in multimedia telephony-over-LAN conferences is described. On establishment of a VoIP session the clients involved are checked for the capability of IM and if capable, also the IM service is started at the clients. The system described in EP 1 377 005 A1 however allows no user interaction or service selection.
Applications for implementing value added services typically require an application session to be started and to be explicitly configured for telephony. The application will then call all participants or the participants have to dial in to a special conferencing phone number. The system described in EP 1 517 506 A2 comprises, for instance, a server which contains a module for instructing two or more multimedia endpoints to call a dial number for establishing a multimedia conference. The method and system for improving the establishment of a multimedia session described in EP 1 517 506 A2 further requires the services to be selected by the session initiator prior to session establishment.
In EP 1 487 167 A1 a method is described for providing additional services to a called user terminal, wherein the called participant can select additional services at call signaling time. For this purpose a call session control network element and a primary application server are provided which are adapted to select and invoke according application servers at call signaling time.
The establishment of additional service sessions during a running session is however not possible in any of the prior art systems described above.